B 612 – 00 Designation B 612 – 00 Standard Specification for Iron Bronze Sintered Bearings (Oil Impregnated) 1 This standard is issued under the fixed designation B 612; the number immediately followi[.]
Designation: B 612 – 00 Standard Specification for Iron Bronze Sintered Bearings (Oil-Impregnated)1 This standard is issued under the fixed designation B 612; the number immediately following the designation indicates the year of original adoption or, in the case of revision, the year of last revision A number in parentheses indicates the year of last reapproval A superscript epsilon (e) indicates an editorial change since the last revision or reapproval This standard has been approved for use by agencies of the Department of Defense TABLE Chemical Requirements Scope 1.1 This specification covers iron-copper-tin-graphite sintered metal powder oil-impregnated bearings of one composition commonly known as diluted bronze 1.2 The following safety hazards caveat pertains only to the test method described in this specification: This standard does not purport to address all of the safety concerns, if any, associated with its use It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use Element Composition, % Iron Copper Tin Total carbon Combined carbonA Total other elements A 54.2–62.0 34.0–38.0 3.5–4.5 0.5–1.3 0.5 max 2.0 max On basis of iron Physical Properties 6.1 Density—The density of bearings supplied fully impregnated with lubricant shall be 6.0 to 6.4 g/cm3 6.2 Oil Content—Oil content of bearings shall not be less than 17 % when determined in accordance with Test Method B 328 6.3 Radial Crushing Strength—Radial crushing strength determined as prescribed in 9.2 shall be not less than nor greater than the calculated value limits using the minimum and maximum K values given below and using the following equation: Referenced Documents 2.1 ASTM Standards: B 328 Test Method for Density, Oil Content, and Interconnected Porosity of Sintered Powder Metal Structural Parts and Oil-Impregnated Bearings2 E Test Methods of Compression Testing of Metallic Materials at Room Temperature3 Ordering Information 3.1 Orders for material under this specification shall include the following information: 3.1.1 Dimensions and 3.1.2 Certification (12.1) P KLT2/~D T! (1) where: P = radial crushing strength (Note), lbs (or N); D = outside diameter of bearing, in (or mm); T = wall thickness of bearing, in (or mm); L = length thickness of bearing, in (or mm); and K = strength constant with Kmin = 22 000 psi (152 MPa) and Kmax = 50 000 psi (345 MPa) Materials and Manufacture 4.1 Bearings shall be made by briquetting and sintering metal powders with an addition of graphite so as to produce finished parts conforming to the requirements of this specification NOTE 1—Strengths above the maximum value indicate high combined carbon, which has a deleterious effect on bearing performance Chemical Composition 5.1 The material shall conform to the requirements as to chemical composition prescribed in Table Workmanship, Finish, and Appearance 7.1 Bearings shall be uniform in composition When cut or fractured, the exposed surface shall be of uniform appearance The parts shall be free of defects which would affect their serviceability Upon metallographic examination, the microstructure of the material shall be iron dispersed through a matrix of substantially alpha bronze and containing no free tin visible at 3003 To check for uniform permeability, the part shall be observed either while it is being heated or while the inside of the bearing is being subjected to air pressure Oil shall exude uniformly from all critical surfaces This specification is under the jurisdiction of ASTM Committee B-9 on Metal Powders and Metal Powder Products and is the direct responsibility of Subcommittee B09.04 on Bearings Current edition approved October 10, 2000 Published December 2000 Originally published as B 612 – 76 Last previous edition B 612 – 96 Annual Book of ASTM Standards, Vol 02.05 Annual Book of ASTM Standards, Vol 03.01 Copyright © ASTM, 100 Barr Harbor Drive, West Conshohocken, PA 19428-2959, United States B 612 section shall meet the minimum strength requirements prescribed in 6.3 Sampling 8.1 Lot—Unless otherwise specified, a lot shall consist of parts of the same form and dimensions made from powders of the same composition, formed and sintered under the same conditions, and submitted for inspection at one time 8.2 Sample for Chemical Analysis—At least one sample for chemical analysis shall be taken from each lot A sample shall consist of not less than oz (56 g) of chips obtained by milling or drilling from at least two pieces with clean dry tools without lubrication To obtain oil-free chips, the parts selected for test shall be extracted in accordance with Test Method B 328, if necessary 8.3 Mechanical Tests—The manufacturer and purchaser shall agree on a representative number of test pieces 10 Inspection 10.1 Unless otherwise specified, inspection of parts supplied on contract shall be made by the purchaser at the destination 11 Rejection 11.1 Unless otherwise specified, rejection based on tests made in accordance with this specification shall be reported to the manufacturer within 30 days from receipt of the material by the purchaser 12 Certification 12.1 A certification based on the manufacturer’s quality control that the material conforms to the requirements of this specification shall be the basis of shipment of the material A certificate covering the conformance of the material to this specification shall be furnished by the manufacturer upon request of the purchaser Test Methods 9.1 Density—Test Method B 328 9.2 Radial Crushing Strength—Compress the test specimens between two flat surfaces at a “no load” speed no greater than 0.2 in./min (5.0 mm/min), the direction of the load being normal to the longitudinal axis of the specimen The point at which the load drops as a result of the first crack shall be considered the crushing strength Apply this test to plain cylindrical bearings Test flanged bearings by cutting off the flange and compressing the two sections separately Each 13 Keywords 13.1 density; K strength constant; oil content; oilimpregnated bearings; porosity APPENDIX (Nonmandatory Information) X1 EXPLANATORY INFORMATION TABLE X1.1 Permissible Loads X1.1 Design Information X1.1.1 In calculating permissible loads, the operating conditions, housing conditions, and construction should be considered The maximum static bearing load should not exceed 8500 psi (60 MPa) of projected bearing area (length times inside diameter of bearing) for this material This figure is 75 % of the value for the compression deformation limit (yield strength, permanent set of 0.001 in (0.025 mm) for specimens 11⁄8 in (28.6 mm) in diameter and in (25.4 mm) in length) as determined in accordance with Test Methods E Shaft Velocity, ft/min (m/min) Slow and intermittent 25 (7.6) 50 to 100 (15.2 to 30.4), incl Over 100 to 150 (30.4 to 45.7), incl Over 150 to 200 (45.7 to 61), incl Over 200 (61) Permissible Loads, psi (MPa) 4000 2000 400 300 200 (28) (14) (2.8) (2.1) (1.4) A A For shaft velocities over 200 ft/min (61 m/min), the permissible loads may be calculated as follows: P 40 000/V X1.2 Permissible Loads X1.2.1 Permissible loads for various operating conditions are given in Table X1.1 where: P = safe load, psi of projected area and V = shaft velocity, ft/min In SI units: P 85/V X1.3 Dimensional Tolerances X1.3.1 Commercial dimensional tolerances are given in Table X1.2 where: P = is in MPa and V = is in m/min and should not exceed 400 ft/min (122 m/min) X1.4 Press Fits X1.4.1 Plain cylindrical journal bearings are commonly installed by press fitting the bearing into a housing with an insertion arbor For housings rigid enough to withstand the press fit without appreciable distortion and for bearings with wall thickness approximately one eighth of the bearing outside diameter, the press fits shown in Table X1.3 are recommended X1.5 Running Clearance X1.5.1 Proper running clearance for sintered bearings depends to a great extent on the particular application Therefore, only minimum recommended clearances are listed in Table B 612 TABLE X1.2 Commercial Dimensional Tolerances NOTE 1—This table is intended for bearings with a to maximum length to inside diameter ratio and a 24 to maximum length to wall thickness ratio Bearings having greater ratios than these are not covered by the table Total Diameter ToleranceA Inside Diameter and Outside Diameter Inside Diameter in Up to 1.511 2.511 3.011 4.011 5.011 mm 1.510 to 2.510 to 3.010 to 4.010 to 5.010 to 6.010 up to 38.36 38.37 to 63.76 63.77 to 76.46 76.47 to 101.86 101.87 to 127.26 127.27 to 152.65 Outside Diameter in mm in mm 0.001 0.0015 0.002 0.003 0.004 0.005 0.025 0.04 0.05 0.08 0.10 0.13 0.001 0.0015 0.002 0.003 0.004 0.005 0.025 0.04 0.05 0.08 0.10 0.13 Total Length ToleranceB Length in Up to 1.495 1.496 to 2.990 2.991 to 4.985 mm up to 37.97 37.98 to 75.96 75.97 to 126.61 Outside Diameter mm 1.010 to 1.510 to 2.010 to 3.010 to 4.010 to 5.010 to 6.010 mm 0.25 0.38 0.51 Concentricity ToleranceC Wall Thickness, max in Up to 1.011 1.511 2.011 3.011 4.011 5.011 in 0.010 0.015 0.020 in up to 25.66 25.67 to 38.36 38.37 to 51.06 51.07 to 76.46 76.47 to 101.86 101.87 to 127.26 127.27 to 152.65 up up up up up up up to to to to to to to 0.255 0.355 0.505 0.760 1.010 1.510 2.010 mm in mm 6.48 9.02 12.83 19.30 25.65 38.35 51.05 0.003 0.003 0.004 0.005 0.005 0.006 0.007 0.08 0.08 0.10 0.13 0.13 0.15 0.18 A Total tolerance on the inside diameter and outside diameter is a minus tolerance only Total tolerance is split into plus and minus C Total indicator reading B TABLE X1.3 Recommended Press Fits Press Fit Outside Diameter of Bearing in Up to 0.760 0.761 to 1.510 1.511 to 2.510 2.511 to 3.010 Over 3.010 max mm in mm in mm up to 19.31 19.32 to 38.36 38.37 to 63.76 63.77 to 76.45 over 76.45 0.001 0.0015 0.002 0.002 0.002 0.025 0.04 0.05 0.05 0.05 0.003 0.004 0.005 0.006 0.007 0.08 0.10 0.13 0.15 0.18 X1.4 The maximum running clearances will automatically be held within good design practice for average conditions if dimensions shown in the standard size list in Table X1.5 are used It is assumed that ground steel shafting will be used and that all bearings will be oil impregnated X1.7 Flange and Thrust-Bearing Specifications X1.6 Standard Sleeve Bearing Sizes X1.6.1 The standard size list shown in Table X1.5 is adaptable to the basic shaft and basic hole systems through control of the insertion arbor diameter It is based on dimensional tolerances shown in Table X1.2 and on tables of recommended press fits, Table X1.3, and running clearances, Table X1.4 X1.8 Impregnating Oil X1.7.1 Diameter and thickness specifications for flange and thrust washers are shown in Table X1.6 X1.8.1 It was found that a circulating-type oil containing rust and oxidation inhibitors is the most desirable type of oil to be used The viscosity should be specified by the user in accordance with the application TABLE X1.4 Running Clearances Shaft Size in 0.000 to 0.760 0.761 to 1.510 1.511 to 2.510 Over 2.510 Clearance, mm 0.00 to 19.31 19.32 to 38.36 38.37 to 63.76 over 63.76 in mm 0.0005 0.001 0.0015 0.002 0.01 0.025 0.04 0.05 B 612 TABLE X1.5 Standard Sleeve Bearing Size Specifications Inside Diameter Decimal Fractional, in Outside Diameter Wall Thickness, in Length Fractional, in in mm ⁄ 1⁄8 5⁄32 3⁄16 3⁄16 0.127 0.127 0.158 0.1895 0.1895 3.23 3.23 4.01 4.80 4.80 32 ⁄ ⁄ ⁄ ⁄ 6.40 6.40 7.99 7.99 9.58 9.58 16 38 0.252 0.252 0.3145 0.3145 0.377 0.377 ⁄ ⁄ 5⁄8 5⁄8 3⁄4 3⁄4 0.502 0.502 0.627 0.627 0.752 0.752 12.75 12.75 15.925 15.925 19.10 19.10 16 58 ⁄ 34 1 11⁄4 11⁄4 11⁄2 11⁄2 1.003 1.003 1.2535 1.2535 1.504 1.504 25.48 25.48 31.84 31.84 38.20 38.20 18 21⁄2 2.004 2.505 50.90 63.63 14 3.006 76.35 14 18 14 14 ⁄ ⁄ 16 16 38 12 12 Decimal in mm in mm ⁄ 1⁄4 1⁄4 5⁄16 0.1905 0.253 0.253 0.253 0.3155 4.83 6.43 6.43 6.43 8.01 0.250 0.250 0.312 0.375 0.375 6.35 6.35 7.92 9.525 9.525 ⁄ ⁄ 7⁄16 1⁄2 1⁄2 9⁄16 0.378 0.4405 0.4405 0.503 0.503 0.5655 9.60 11.19 11.19 12.78 12.78 14.36 0.500 0.500 0.562 0.562 0.625 0.625 12.70 12.70 14.275 14.275 15.875 15.875 ⁄ ⁄ 3⁄4 7⁄8 7⁄8 0.628 0.753 0.753 0.879 0.879 1.004 15.95 19.13 19.13 22.33 22.33 25.50 0.750 0.750 0.750 0.937 1.125 1.125 19.05 19.05 19.05 23.80 28.575 28.575 16 11⁄4 13⁄8 11⁄2 15⁄8 13⁄4 17⁄8 1.254 1.379 1.504 1.630 1.755 1.880 31.85 35.03 38.20 41.40 44.58 47.75 1.500 1.500 1.500 1.875 1.500 2.250 38.10 38.10 38.10 47.625 38.10 57.15 14 ⁄ ⁄ 21⁄2 2.505 3.006 63.63 76.35 2.000 2.500 50.80 63.50 ⁄ 31⁄2 3.507 89.08 3.000 76.20 ⁄ 1⁄16 3⁄64 1⁄32 1⁄16 ⁄ 16 14 ⁄ ⁄ 1⁄16 3⁄32 1⁄16 3⁄32 38 32 16 ⁄ 18 ⁄ 16 ⁄ 18 ⁄ 16 ⁄ 18 ⁄ ⁄ 16 ⁄ 18 ⁄ 16 ⁄ 18 ⁄ TABLE X1.6 Flange and Thrust Bearings Diameter and Thickness TolerancesA Diameter Range in to 11⁄2 Over 11⁄2 to Over to mm to 38 39 to 76 77 to 152 Diameter Range in to ⁄2 Over 11⁄2 to Over to mm to 38 39 to 76 77 to 152 in 60.005 Special in 60.0025 60.005 60.010 mm to 38 39 to 76 77 to 152 Parallelism on Faces, max Standard in mm 0.003 0.08 0.004 0.10 0.005 0.13 mm 60.06 60.13 60.25 Special in 60.0025 60.007 60.010 Thrust Bearings (1⁄4-in (6.35-mm) Thickness, max), Thickness Tolerances for All DiametersA,B Standard Special mm in 60.13 60.0025 Diameter Range in to 11⁄2 Over 11⁄2 to Over to Flange Bearings, Flange Diameter Tolerances Standard in mm 60.005 60.13 60.010 60.25 60.025 60.64 Flange Bearings, Flange Thickness Tolerances Standard in mm 60.005 60.13 60.010 60.25 60.015 60.38 mm 60.06 60.18 60.25 mm 60.06 Special in 0.002 0.003 0.004 mm 0.05 0.08 0.10 A Standard and special tolerances are specified for diameters, thickness and parallelism Special tolerances should not be specified unless required since they require additional or secondary operations and, therefore, are costlier B Outside diameter tolerances are the same as for flange bearings The American Society for Testing and Materials takes no position respecting the validity of any patent rights asserted in connection with any item mentioned in this standard Users of this standard are expressly advised that determination of the validity of any such patent rights, and the risk of infringement of such rights, are entirely their own responsibility This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years and if not revised, either reapproved or withdrawn Your comments are invited either for revision of this standard or for additional standards and should be addressed to ASTM Headquarters Your comments will receive careful consideration at a meeting of the responsible technical committee, which you may attend If you feel that your comments have not received a fair hearing you should make your views known to the ASTM Committee on Standards, at the address shown below B 612 This standard is copyrighted by ASTM, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the above address or at 610-832-9585 (phone), 610-832-9555 (fax), or service@astm.org (e-mail); or through 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